While the Beatles were working on Abbey Road, Frank Zappa was playing around with Hot Rats. This was the way fusion should have sounded . . . raising rock to a higher level of musicianship and creativity, rather than packaging watered-down jazz for the masses. "The Gumbo Variations" is a hard-grooving 17-minute jam with one of the tightest rhythm sections you have ever heard on a jazz-rock album. And the solos are topnotch -- Ian Underwood's tenor sax outing deserves your immediate attention, and Zappa scorches everything in sight with his guitar work.